Portable fire alarm



I a Y 1,624,866 April 12 1927' A. M. DE s. GRE/was PORTABLE FIRE ALARM Filed Jan.17,. 1922 Patented Apr. 12, 1927.

y UNITED 'STATES PATENT oFFicE.

.ABILIO M. DE SILVA GREAVES, OF CAMBRIDGE, MASSACHUSETTS.

PORTABLE FIRE ALARM.

Application led January 17, 1922. L'Serial No. 529,866. A

This invention relates to a portable lire alarm, and lone of its objects is to provide an electrical alarm device which is simple and inexpensive in construction, reliable and eilicientv in operation, and adapted to be placed` for use as desired in any room or otherportion of a building, so as to be into provide an alarmdevice of suchsimplicity, small size and ready portability as to be cheapl furnished for household use or to be carrie by travelers for their use in hotels and the like. The invention consists of the features of construction, combination and arrangement of parts, hereinafter fully described and claimed, reference being had to the accompanying drawing, in which:- y Figure 1 is a perspective view of the alarm device in complete form for use.

Figure 2 is a front view of the same with the .front door of the casing thrown open to expose the interior thereof.

Figure 3 is a horizontal section on lilie 3 3 of'Figure 2.

Figure 4 is a detail view of the thermostatic circuit closer. v

Figure 5 is a face view of the backing plate. l f

Figure 6 is a rear view of the same.

Fi re 7 is a4 view of the insulating or .shiel plate.

Figure 8 is a diagrammatic View'` of the electric circuit.

In carrying my invention into practice, I provide a casing 1 to enclose the working parts, the body of saidv casing bein open at the front and adapted to be close by a v150 hinged door or cover 2, secured normally in closed position by' a spring clip or other suitable fastener 4. Said casing may be of oblong rectangular form or otherA suitable form, and the body or the cover member thereof is provided in its bottom sull with air inlet openings 4 and in its top wall with air outlet openings 5. These openings permit air to circulate through the casing, so that the circuit controlling connection inside the casing may be directly influenced by heated air, when the temperature rises to a certain degree, in order to effect the actuation of the alarm.

Arranged within thebodytof the casing is a backing or support -6 comprising a sheet of fiber or other suitable `non-conducting material. This sheet 6 is disposed adjacent 'to the front wall of the body` of the casing,

and disposed between said sheet 6 and the front wall of the casing is a similar sheet serving as a protector for certain parts of the electrical connections and to insulate the same from the wall of the casing to obviate liability of short circuiting.

Supported by the sheet 6 is a `thermostatic circuit closercomprising a mercury tube 8 communicating at its lower end with a mercury containing bulb 9 and having at its upper end an expansion chamber 10 into ywhich project the circuit closing contacts l1.

The lower ends of these contacts 11 are suitably spaced and terminate in line with the bore of the tube 8 and adjacent to its point 0f,0ommunication with the chamber 1.0, so Y that said contacts will be connected by the mercury flowing from the vbore into the exparisien chamber, to complete the circuit, when the temperature rises to the predetermined degree. The contacts 11 are fixed at their upper ends to threaded stems 12 engaging threaded openings in the top of a supporting block or base 13 on which the thermostatic circuit closer is mounted, said stems 12 forming binding posts for the attachment of conducting wires, as hereinafter described.

The alarm circuit controlled by the said thermostatic circuit closer includes a pair oil?r dry battery cells r14 and 15, disposed vertically on opposite sides of the thermostatic circuit closer, which circuit closer'is referably arranged. at a central position within the casing and between said battery cells. Each battery cell is clamped between a pair of Pspring clips 16 and v17 carried by the backing 6,' and these spring .clips 16 and 17 also form contacts for engagement with the opposite poles of the battery. In applying each battery for use, it is inserted through the open front of the casing between the clips 16 and 1"( which yield to permit itto enter between them, and then the clips A.so

spring back by their resiliency and engage the exposed poles of the battery at the ends thereof and clamp said battery in place. In addition a spring clip or4 finger 18 may be provided upon the backing sheet to en gage the inner side of each battery cell and hold it pressed against the adjacent side wal-l of the casing body, the several clips 16, 17 and 18 forming supports which hold the battery securely in position against casual displacement while admitting of its ready removal and replacement whenever occasion reqiures.

The contacts 16 and 17 associated with the respective cells 14 and 15 are reversed in their order of arrangement, As shown particularly in Figure 6, the lower contacts 16 and 17 engaging unlike poles at the lower ends of the cells, are connected by a conducting strip 19 uniting said contacts at the back of the sheet 6, while the upper set of contacts 16 and 17 engaging unlike poles at the upper ends ofthe batteries are normally electrically disconnected. Suitably mounted upon the front wall of the casing is a bell or other desired type of signal, and extending from the upperI battery contact 16 to one pole of this bell is a conducting wire 21 which passes through registering openings 22 formed inthe sheets 6 and 7. The other pole of the bell 20 is connected by a conductor 23 with the binding post 12 of one of the circuit closing contacts 11, with which bindingl post is also connected another conductor the second 'conductor 23 extending between said bell and binding post through registering openings 25 in the sheetsl 6 and 7. Conductor 24 is secured to and electrically connected with a junction plate 26 mounted on the backing 6, and also secured lto said junction plate 26 and electrically connected with the conductor 24 is a conductor 27.

It will be observed from the foregoing that the upper pole of battery 14 is connected by conductor 21 with one pole of the bell 20, the other pole of which bell is connected with one of the circuit closing contacts 11. Also it will observed that the lower pole of battery 14 is permanently connected by means of the conductor 19 with the lower pole ofbattery 15. The upper pole of battery 15 is connected with a conductor 28 which comprises a metallic strip arranged upon the back of the sheet 6, much the same as is member 19, and extending between the battery contact 17 and a junction plate 29 supported by the sheet 6, to which junction Vplate is secured and electrically connected a conductor 30 leading to the binding post 12 of the other circuit closing contact 11. Also secured to and electric-ally connected with the junction plate 29 is a conductor 31. The circuit connections above described, exclusive of the conductors 27 and 31, form, with the batteries 14 and 15 and the thermostatic circuit closing device, a complete electric alarm circuit within the casing which, when energized, will sound the bell or signal 20. The conductors 27 and 31 lead outwardly from the casing through an opening 32 and' may form component parts of an outside circuit V4which may be energized by the said enclosed circuitjfor the purpose of actuating an alarm or annunciator at a distance, as hereinafter described.

In practice, the alarm device embodying the parts and connections above set forth, and which is completely enclosed within the casing orcontainer 1-2, may be made of very small size and of such compact shape that it may be carried in the pocket or within a traveling case so that it is readily portable and may be mounted for use wherever desired. While the bell is described as being mounted upon casing body 1, it may, of course, be mounted upon the casing cover 2. As shown in the present instance, the cover 2 is arranged to form the back part of the casing, and is designed to be fastened in any desired manner upon a wall, door frame or other support, leaving the body portion 1 free to be opened or closed on the hinged connection between the same and the cover. This arrangement, however, may be reversed, as will be apparent from the foregoing description. The device as thus constructed may be mounted vertically, as stated, or may be arranged upon any suitable support for use in any room or portion of a house or other building, so that in the event of a fire breaking out in the immediate vicinity in which it is located the mercury expanding and rising in-the tubev8 will connect thc contacts 11 and energize the alarm circuit to sound the alarm bell 20, thus warning the occupants of the room or building of the impending danger. It therefore provides a convenient alarm device for the use of householders who may desire to place a signal alarm device at any point withinv the house, and it may also be employed in a convenient manner by travelers who desire to carry an alarm device with them to give warning in the event of fire breaking out in their room or in an adjacent portion of va hotel at which they are stopping. The device is also Vwell adapted for the use of campers and others who desire to employ a protecting device of this kind. By the use of the conductors4 27 and 31, which may be extended to any part of a house or building, the alarm device may also be employed to operate one or more distant alarm devices located at one or more points in a building, for giving a general alarm when the circuit of the alarm device in question is closed by the thermostatic circuit closer. The contacts 27 and 31 may also be connected with an annunciator, such as shown diametrically in Figure 8 located at a main point in a building so as to indicate l employed for the stated purpose, whereby the occupant of the room will not only be advised of the breaking out of the fire but such information willalso be communicated to the main oiice or some other point of a hotel, apartment house or other building to give additional warning of the breaking out of a fire.

As stated, the batteries 14 and 15 are secured in position in a manner to admit ot' their ready and convenient insertion and removal. The thermostatic circuit closer may also be removably secured in position by clips 33 anchored in the backing 6, .and the wires 24, 25 and 30 in conjunction with the junction plates 26 and 29 will additionally serve to hold the thermostatic circuit clos-` ing device in position against liability of casual displacement, while admitting of its ready and convenient removal.

Having thus fully described I claim 1. A portable fire alarm comprising a. ca sing, a non-conducting backing sheet within the casing, two pairs'of spring contacts carried by the backing sheet, a dryy cell arraneed between each pair of spring contacts adjacent to the sides of the casingand having the poles thereof engaged by said contacts, clips carried by the backing sheet and holding the cells pressed against the sides of the casing, a conducting connection between a spring contact of one pair of contacts and a spring contact of the other pair of contacts, an alarm device on the casing, conductors associated with said contacts and forming therewith and with said dry cells an electric circuit in which said alarm .device is arranged,

my invention,

circuit closing contacts in said circuit, and

a thermostatic circuit closer enclosed 'within said casing for electricallyconnecting said circuit closing4 contacts at a predetermined temperature.

2. A portable fire alarm comprising a casing, a non-conducting backlng sheet within the casing, dry cells disposed at opposite sides of the casing, pairs of spring clips secured to the backing sheet yand engaging the poles of each cell and holding said Acells in position, a thermostatic circuit closer supported upon the backing sheet between said cells and having circuit closing contacts, an electrical connection between two spring clips engaging opposite polesof the cells, a pair of junction plates, an electrical connection between one of said junction plates and one of the other cell clips, electrical connec` tions between the junction plates and the circuit closing contacts, a bell, a conducting connection between one terminal of the bell and the remaining cell clip, and a conducting connection between the other terminal of the bell and the junction plate connected with the other cell clip of the same pair.

3. A portable fire alarm comprising a casing, a backing sheet within said casing, dry cells disposed on opposite sides of the center of the casing at the front of said backing sheet, an upper and a lower spring clip for each dry cell engaging the poles thereof, side clips for holding said cells pressed against the sides'of the casing, a thermostatic circuit closer supported upon /the backing sheet between the dry cells, said thermostatic'circuit closing device having contact points, an electrical connection between two of the pole engaging clips of the cells, a pair ofrjunction plates supported by the backing sheet, electrical connections between the same and the circuit closing contacts, a conducting connection between one of said junction plates and one of the other pair. of spring clips, a bell supported by the casing, a conducting connection between one pole of the bell and the remaining spring clip, a conducting con# nection between the other poleof the bell and the otherjunction plate, certain of said conductors being disposed upon the rear of the backing sheet, and an insulating covering between said connections and a casing.

In testimony whereof I affix my signature.

ABILIO M. DE SILVA GREAVES.

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